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Systemic Lupus Erythematosus (Lupus)
in Children and Adolescents
What
tests are done in lupus?
Laboratory tests can help diagnose lupus and decide which, if any, organs are
involved. In addition, regular
testing of blood and urine after lupus is diagnosed can be very useful in
monitoring the activity and severity of the disease, as well as how well the
medications are tolerated.
Lupus is a
disease which fluctuates; it can flare and then settle down again at any time. Often,
in children and adolescents, monitoring tests can predict flares. In other words, the tests become abnormal before symptoms
occur, and treatment started or increased at this stage may prevent further
problems. One of the reasons
for seeing your doctor so often, even though you may feel well, is to get these
monitoring tests done. Some of the
tests available for lupus are listed below.
Antinuclear
antibodies (ANA): a blood test that is positive in almost all patients with
lupus, but which can also be positive in other diseases and even in children
without any disease. This is a sort
of a screening test for lupus. It
usually stays positive for a long time.
Anti-double
stranded (native) DNA antibodies (anti-DNA): a blood test that is positive in
most patients with lupus and not in people with other diseases. Levels of this antibody can be very useful in monitoring activity of
lupus and predicting flares. Your
doctor may do this test often. During
remissions this test may be negative or low and during flares it may be
positive.
Other
autoantibody tests: these are
positive in some patients with lupus. Your
doctor may do them initially and then again at certain times.
Full
blood counts: these tests count all the cells in a small sample of blood. They are also useful at the time of diagnosis and monitoring.
Some of the cells may be reduced in number in lupus, especially the red
cells (which carry oxygen from the lungs to other parts of the body), or
platelets (which help the blood clot properly) or white cells particularly the
lymphocytes (see The Immune System).
Blood
tests for inflammation: these tests measure different substances that can be
found in the blood when inflammation is present.
Complements:
these tests measure levels of certain proteins which may be lowered when immune
complexes circulate in the blood stream or deposit in tissues. Your doctor may do these tests each time you come for a visit to monitor
the activity of your lupus.
Urine
tests: these are very important at
the time of diagnosis of lupus and each time you see your doctor because they
help determine kidney involvement. Because
urine is made in the kidneys, your doctor
can see if your kidneys are affected by lupus by testing the urine to see if there is blood, protein, and broken up
cells called "casts." Sometimes,
you may be asked to collect your urine for 24 hours and based on the findings
your doctor may recommend a kidney biopsy (taking a tiny sample of your kidney
tissue itself for analysis).
Other
tests: many other tests are now
available to your doctor to look at the effects of lupus on different parts of
your body. Most of these are blood
tests that help determine how well the organs such as the liver, kidney or bone
marrow are working. Other tests are
more cumbersome than blood and urine studies and may require a separate trip to
the hospital. Fortunately, these
tests are only done if needed and are not necessary in all patients. They include chest x-rays (for heart and
lungs), ECG and echogram for the
heart, pulmonary functions for the lungs, EEG, MR, or other scans for the brain,
and possibly various tissue biopsies. Be
sure to understand what the tests are for if your doctor recommends them.
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